CN209945737U - A simulation test system for large diameter earth pressure shield tunnel excavation interface - Google Patents

Abstract

The utility model discloses a major diameter earth pressure shield tunnel tunnelling interface analogue test system. Filling a soil sample in a model box for placing a shield model, wherein the shield tunneling system comprises a soil bin control device and a soil discharging and water discharging control device and is used for simulating a shield tunneling process; the water level control system sends water to the model boxes at different heights to realize underground water level simulation; the seepage tracing device traces the seepage streamline distribution at the position by the diffusion of the pigment under the seepage action; the monitoring system comprises a digital photographic camera and soil and water pressure sensors and is used for monitoring the deformation of a soil body of the driving face, the pressure distribution of the soil bin and the fluctuation rule. The utility model discloses a set up different water level height, tunnelling speed, monitoring soil body is out of shape, soil storehouse pressure fluctuation and seepage flow distribution for the groundwater seepage law and the unstability characteristic of major diameter shield driving face in the research infiltration stratum make effectual early warning to driving face unstability, and then establish and correspond the unstability mechanism.

Description

A simulation test system for large diameter earth pressure shield tunnel excavation interface

technical field

The utility model relates to a simulation test system for a tunnel excavation interface, in particular to a simulation test system for the excavation surface of a large-diameter earth pressure shield tunnel.

Background technique

At present, the earth pressure shield construction is developing in the direction of large diameter and large buried depth. In the actual excavation process, under the influence of factors such as the rotation of the cutter head, excavation, shield advancement, and injection of lubricant and foaming agent, the pressure of the soil bin often fluctuates continuously. With the increase of the diameter of the earth pressure shield, the pressure difference at different heights in the soil bin becomes more pronounced. Under the disturbance of the excavation, it is easy to form an obvious low pressure area in the middle and upper part of the soil bin, which leads to insufficient support load in local areas, and strain localization occurs first in some areas. feature. It is not uncommon for earth pressure shield tunneling in permeable strata to cause driving face instability and stratum collapse accidents. Under the action of seepage, the localized strain develops rapidly, and a continuous shear zone is gradually formed, and the unstable soil slips along the shear zone. Collapse damage.

With the advancement of test technology, model test has been applied to the research on the stability of shield tunneling surface because it can more realistically reflect the process of soil instability. Before the present utility model is made, the Chinese invention patent with the publication number CN105019920A relates to a shallow buried underground tunnel formation deformation test system, which aims to provide a shallow buried underground tunnel formation deformation test system under advanced reinforcement; The retreat of the mobile panel simulates the stress release under a single footage of shallow burial. Through the monitoring of the surface settlement, the change of the axial force, the retreat speed and the advanced reinforcement setting of different combinations of the grouting pipe shed, the law of the surface settlement and the stress release of the excavation surface are studied. The model test was carried out under dry sand conditions. It mainly measured the surface settlement deformation and the change law of the axial force of the excavation face under different advanced reinforcement forms. The influence of seepage on the stability of the excavation face was not involved. The realization is quite different from the actual shield tunneling behavior, and it cannot reflect the characteristics of pressure fluctuations in the soil bins for large-diameter shield tunneling construction.

In order to further study the instability development process of shield tunneling face of medium and large diameter shield tunneling face under the action of groundwater seepage, reveal the stage characteristics of instability failure, and realize the simulation of large diameter shield tunneling behavior in permeable strata, it is of great significance. .

SUMMARY OF THE INVENTION

Aiming at the shortcomings of the prior art, the utility model provides a simulation observation that can realize the instability development process of the large-diameter shield tunneling face under the action of seepage, in order to analyze the stable state of the tunneling face and reveal the large-diameter shield tunneling under the action of seepage. The model test device for simulating the interface behavior of large diameter earth pressure shield tunnel excavation provides experimental basis for the development process and stage characteristics of surface instability.

The technical scheme to achieve the purpose of the invention of the present utility model is to provide a large-diameter earth pressure shield tunnel excavation interface simulation test system, including a model box, a shield model, a monitoring system, and a shield excavation system and a water level control device. Seepage tracer device;

The model box is a rectangular cube, and the surrounding panels are made of transparent high-strength organic materials. One side panel of the model box has a semicircular opening for installing the shield model and an opening for installing the shield tunneling system. There are several openings at different heights on the side panel for installing the water supply pipes of the water level control system; the model box is filled with soil samples;

The shield tunneling system includes a soil bin control device and a soil dumping and drainage control device; the soil bin control device includes a soil bin partition, an axial force gauge, a transmission rod, a recording device, a transmission, a driving device and an external support ; The soil bin partition is a semicircular panel, which is arranged between the inner concave surface of the semi-circular shield model shell and the front panel of the model box, and the bottom of the soil bin partition is provided with a muck outlet; the soil bin partition, axial force The meter and the transmission rod are connected in sequence. The transmission rod passes through the side panel of the model box and is connected to the transmission outside the model box. The transmission is connected with the driving device, and the driving device is fixed on the external support; one end of the recording device is fixed on the external support, One end is connected to the soil bin partition; the soil bin partition moves in the semi-circular shield shell under the control of the transmission rod; the axial force meter is used to test the pressure of the moving panel, and the recording device is used to test the movement The moving distance of the panel; the driving device provides power for the moving panel, and the transmission is used to control the speed of the moving panel forward and backward; the soil and drainage control device includes a conveyor, a power device, a drainage pipeline, a valve, Flow meter, waste water tank, a conveyor is installed at the muck outlet at the lower part of the clapboard of the soil bin, the conveyor passes through the side panel of the model box and is connected to the power unit, which is fixed on the external support; the opening at the bottom of the conveyor is connected to the drainage There are water outlet valves and flow meters on the drain pipe, and the drain pipe is connected with the waste water tank;

The water level control system includes a pressure pump, a supply water tank, a water supply pipe and a valve; the supply water tank and the pressure pump are connected by a water supply pipe; a number of longitudinally arranged water supply pipes pass through the opening on one side panel of the model box and are inserted into the model box In the filled soil samples at different heights, the outlet of the water supply pipe is sealed with a filter membrane; the water supply pipe is provided with a valve to control the water level in the model box, and the open valves of the water supply pipe at different heights are selected to control the soil filling in the model box. Irrigation of the sample is carried out, so that the soil sample above the water level is in an unsaturated state, and the groundwater level simulation is realized;

The seepage tracing device is installed on the top of the model box, and the seepage tracing device includes a paint tube and a paint supply tank. Several paint tubes are inserted from the top of the model box along the axis direction into the shallow soil layer filled with soil samples in the model box. It is arranged near the front panel in the model box; there is a valve on the paint tube to control the replenishment of paint;

The monitoring system includes a digital photographic camera, soil and water pressure sensors; the digital photographic camera is arranged outside the front panel of the model box, and is used to record the change of the soil sample in front of the excavation front during the test process; the soil and water pressure sensors are arranged in the soil bin The clapboard is used to observe the pressure distribution and fluctuation law of the driving face.

The interior space in front of the partition plate of the soil bin of the shield model of the utility model is filled with improved slag, simulating the improvement of the excavated soil in the soil bin of a large-scale earth pressure shield machine.

The driving device and the power device adopt a servo motor.

The recording device uses a linear displacement sensor.

The conveyor adopts a tubular screw conveyor, and the screw speed is controlled by a power device to realize quantitative soil discharge and drainage control; the pipe of the tubular screw conveyor is pre-filled with sealing glue. The conveyor is opened at the bottom near the muck outlet, the opening is sealed with a filter membrane, and the drain pipe is connected.

The utility model is provided with a supplementary light source outside the front panel of the model box.

Using the large-diameter earth pressure shield tunnel excavation interface simulation test system provided in this embodiment, different test conditions can be set to carry out the following control tests:

Under the condition that the groundwater level and the soil discharge speed of the conveyor remain unchanged, different propelling speeds of the soil bin partitions are set to study the influence of the driving speed on the instability of the driving surface; Then, set the soil dumping speed of different conveyors to study the influence of soil dumping speed on the instability of the driving face.

Different groundwater levels are set, and the seepage effect is more obvious when the groundwater level is higher. The influence of seepage on the stability of the excavation face is analyzed, and the instability mechanism of the excavation face induced by seepage is revealed.

The shield model was not filled or filled with different modified slag prepared in the laboratory test, and the inhibitory effect of different modified slag on seepage was compared and analyzed.

The utility model can be operated according to the following steps when it is implemented

Before the test, a simulation test system was installed. When there was no soil sample in the box, the moving speed of the soil bin partition and the axial force meter readings generated by the friction between the panel and the semi-circular shield shell at different speeds were calibrated. Then move the soil bin partition to 1/3 of the front end of the semicircular shield shell, and fill the interior space in front of the partition of the shield model with improved slag, simulating the excavation soil in the soil bin of the large-scale earth pressure shield machine. body improvement.

After that, the soil samples were filled in the model box by the falling rain method, and then the paint tube was set along the front panel of the model box, and the outlet was buried in the shallow soil layer. The shield tunneling simulation is realized by the forward speed of the soil bin clapboard, and the soil dumping speed of the conveyor is controlled to correspond to the advance of the soil bin clapboard, so that the soil dumping amount is equal to the volume reduction of the soil bin, and different groundwater level, soil The forward speed of the silo partition is used to simulate different excavation processes. The soil and water pressure sensors in front of the soil silo clapboard are used to observe the pressure distribution and fluctuation law of the soil silo. The seepage tracer device displays the seepage law of groundwater. The camera recorded pictures can be analyzed by PIV to obtain the displacement field and velocity field of the soil body on the symmetry plane. The change in the reading of the axial force gauge can analyze the stress relief of the excavation face.

The principle of the utility model is as follows: the cross section of the shield machine is circular, and the semicircular shield model is used to analyze the instability development process of the large-diameter shield tunneling face under the action of seepage by using the axis symmetry. The shield excavation system adopts the soil bunker partition to advance and the conveyor to dump soil, simulating the forward excavation and soil dumping behavior of the large earth pressure shield machine, which is close to the actual shield tunneling behavior. Filling the prepared improved slag in the construction model, simulating the process of injecting additives into the soil bin of the actual large-scale earth pressure shield machine and stirring the soil sample to make it reach a better flow-plastic state. Since the higher the groundwater level, the more obvious the seepage effect is. In order to analyze the effect of seepage on the stability of the excavation face and reveal the instability mechanism of the excavation face induced by seepage, the model needs to set different groundwater table heights. The water level control device injects water into the model box through the water outlets set at different heights, and sets different water level heights, so that the soil samples at the bottom of the water level are in a saturated state, and the soil samples at the upper part are in an unsaturated state to simulate the soil samples under the real groundwater level. state. The seepage tracer device traces the streamline at the location by setting up a row of paint tubes in the shallow soil sample along the axis direction, and adding various colors of paint to the tubes. The paint will diffuse under the action of seepage. Distribution law of surface seepage field. The monitoring system is divided into two parts. One is to set an external digital camera on the front panel of the model box to record the changes of the soil sample in front of the excavation during the test process, and then to process the observed images through the particle digital measurement system (PIV). Soil and water pressure sensors are installed in front of the soil field partition to measure the distribution and fluctuation of soil and water pressure on the excavation surface. From this, the stable state of the excavation face is analyzed, and the instability development process and stage characteristics of the large-diameter shield excavation face under the action of seepage are revealed.

Compared with the prior art, the utility model has the following advantages: the key function of the large-diameter earth pressure shield tunnel excavation interface simulation test system provided by the utility model is to realize the instability development process of the large-diameter shield excavation surface under the action of seepage. The simulation observation can make effective early warning for the instability of the driving face, and then establish the corresponding instability mechanism. The shield excavation process is simulated by propelling the soil silo partition and muck transfer, which is closer to the actual shield excavation behavior. By preparing different modified muck soils and filling them in the shield model, the influence of the properties of the modified muck soils on the instability of the excavation surface can be analyzed.

Description of drawings

Fig. 1 is the front view sectional structure schematic diagram of a kind of large-diameter earth pressure shield tunnel excavation interface simulation test system provided by the embodiment of the present utility model;

Fig. 2 is the side view sectional structure schematic diagram of the simulation test system provided by the embodiment of the present utility model;

Fig. 3 is the side view sectional structure schematic diagram of the shield model in the simulation test system;

Fig. 4 is the structural schematic diagram of the shield tunneling system in the simulation test system;

Figure 5 is a partial detail view of the soil dumping and drainage control device in the simulated test system;

6 is a schematic structural diagram of a water level control device and a seepage tracer device in a simulation test system provided by an embodiment of the present invention;

In the figure, 1. Model box; 2. Shield model; 3. Shield tunneling system; 4. Water level control device; 5. Seepage tracer device; 6. Monitoring system; 7. Soil sample; 8. Digital camera; 9. Supplementary light source; 10. Soil and water pressure sensors; 11. Front panel of model box; 12. Semi-circular shield shell; 13. Shield support; 14. Earth bin partition; 15. Axial force gauge; 16. Transmission rod; 17. Linear displacement sensor; 18. Transmission; 19. Servo motor A; 20. Rubber sealing strip; 21. Muck outlet; 22. Conveyor; 23. Servo motor B; 24. Drain pipe; 25. Valve 26. Flow meter; 27. Waste water tank; 28. Sealing mud; 29. Pressure pump; 30. Supply water tank; 31. Water supply pipe; 32. Pigment supply tank;

Detailed ways

The technical solutions of the present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments.

Example 1

This embodiment provides a large-diameter earth pressure shield tunnel excavation interface simulation test system. By setting different water level heights, simulating different excavation speeds, monitoring the seepage process, soil tank pressure fluctuation, soil layer deformation and the axial force of the excavation surface, In order to study the groundwater seepage law and instability characteristics of large-diameter shield tunneling surface in permeable strata.

Referring to Figures 1 and 2, the simulation test system provided in this embodiment includes a model box 1, a shield model 2, a shield tunneling system 3, a water level control device 4, a seepage tracking device 5 and a monitoring system 6. The model box is a rectangular open box on the upper part, which is used to fill the soil sample 7 and place the shield model 2; the surrounding panels of the model box 1 are transparent tempered glass plates, which are convenient for external monitoring and recording of soil layer deformation. The bottom panel of the model box 1 is steel plate. The left and right panels are provided with openings, the opening on the left panel is a semicircular opening with a diameter of 550mm, and the right panel is provided with openings at different heights.

The monitoring system 6 includes a digital photographic camera 8, a supplementary light source 9, and soil and water pressure sensors 10; the digital photographic camera 8 and the supplementary light source 9 are arranged outside the front panel 11 of the model box, and are used to record the soil samples in front of the excavation front during the test. The photos can be analyzed and processed by using PIV; the soil and water pressure sensors 10 are arranged on the clapboard of the soil bunker to observe the pressure distribution and fluctuation law of the driving face.

The shield model 2 is a semi-circular cylindrical model, including a semi-circular shield shell, an inner arc-shaped solid shield support, and the semi-circular outer convex surface of the semi-circular shield shell can match the inner arc surface of the shield support. Fixed; the semi-circular annular shield shell is fixed with the front panel, bottom panel and left panel of the model box by the shield support, and the left side of the semi-circular shield shell is aligned with the opening of the side panel of the model box; the bottom surface of the shield support is fixed on the The bottom panel of the model box ensures that the semi-circular inner concave surface of the semi-circular shield shell faces the front panel of the model box;

Referring to FIG. 3, the shield model is a semi-circular cylindrical model, including a semi-circular shield casing 12 and a shield support 13, which are used to analyze the groundwater on the excavation surface caused by the excavation of the circular-cylindrical shield by using axial symmetry. Seepage law and instability characteristics. The semi-circular shield shell 12 is made of aluminum alloy plated steel, with an inner diameter of 600 mm. The shield support 13 is an inner arc-shaped solid support made of high-strength alloy steel plate. The convex surface can be matched and fixed with the inner arc surface of the shield support 13 . The semi-circular annular shield shell 12 is installed in the model box by using the shield support 13, specifically: the semi-circular shield shell 12 is fixed to the front panel, bottom panel and left panel of the model box by using the shield support 13, and the semi-circular shield The left side of the shell 12 is aligned with the center of the opening of the left panel of the model box, and the bottom surface of the shield support 13 is fixed on the bottom panel of the model box to ensure that the semi-circular inner concave surface of the semi-circular annular shield shell 12 faces the front panel of the model box. The edge of the soil bin partition 14 is pasted with a rubber sealing strip 20, which slightly wipes the semi-circular shield shell 12 to prevent soil samples from entering the shield; the bottom of the soil bin partition 14 is provided with a muck outlet 21 with a diameter of 60mm, which is connected to the soil dumping. , Drainage control device, realizes shield excavation excavation and seepage control; soil and water pressure sensors 10 are arranged on the soil bin partition 14 to observe the pressure distribution and fluctuation law of the excavation surface.

Referring to Figures 4 and 5, the schematic diagram of the structure of the shield tunneling system and the partial details of the soil dumping and drainage control device in the simulation test system provided in this embodiment are respectively.

The shield tunneling system includes soil bin control device and soil dumping and drainage control device. The soil bin control device includes a soil bin partition 14, an axial force gauge 15, a transmission rod 16, a linear displacement sensor 17, a transmission 18, a servo motor A19 and an external support.

The soil bin partition 14 is a semi-circular panel with a radius slightly smaller than the inner diameter of the semi-circular inner concave surface of the semi-circular annular shield shell and is integrally arranged between the inner concave surface of the semi-circular shield shell and the front panel of the model box, with a thickness of 40mm. The interior space in front of the soil bin partition 14 of the shield model is filled with improved slag 34 to simulate the improvement of the excavated soil in the soil bin of the large earth pressure shield machine; the soil and water pressure sensors 10 are arranged on the soil bin partition 14 It is used to observe the pressure distribution and fluctuation law of the driving face.

The soil bin partition 14, the axial force gauge 15, and the transmission rod 16 are connected in sequence. The transmission rod 16 passes through the opening of the left panel of the model box and is connected to the transmission 18 outside the model box. The transmission 18 is connected with the servo motor A19, and the servo motor A19 is fixed on the on the external support. One end of the linear displacement sensor 17 is fixed on the external support, and the other end is connected to the soil bin partition 14 . The soil bin partition 14 is provided with rollers, and the soil bin partition 14 can move in the semi-circular annular shield shell under the control of the transmission rod 16 by using the rollers. The axial force gauge 15 is used to test the pressure on the soil bin partition 14 , and the linear displacement sensor 17 is used to test the moving distance of the soil bin partition 14 . The servo motor A19 provides power for the movement of the soil bin partition 14, and controls the forward and backward speed of the soil bin partition 14 through the transmission 18. The speed should be controlled at 0.02mm/s～0.25mm/s during operation.

The soil dumping and drainage control device includes a conveyor 22, a servo motor B23, a drainage pipe 24, a valve 25, a flow meter 26, and a waste water tank 27. A conveyor 22 is installed at the muck outlet at the lower part of the clapboard, and the conveyor 22 passes through the left side of the model box. The left panel is open and connected to the servo motor B23. The servo motor B23 is fixed on the external support; the conveyor 22 is a tubular screw conveyor with a diameter of 60mm. Realize quantitative soil dumping and drainage control; the conveyor 22 is connected to the drainage pipe 24 at the opening below the muck outlet, and the opening is sealed with a filter membrane to prevent soil samples from entering the drainage pipe 24. The drainage pipe 24 is provided with a valve 25 and a flow meter 26 to drain the water. The pipe 24 is connected to the waste water tank 27 .

Referring to FIG. 6 , it is a schematic structural diagram of the water level control device and the seepage tracer device in the simulation test system provided in this embodiment.

The water level control system includes a pressure pump 29 , a supply water tank 30 , a water supply pipe 31 and a valve 25 . The water supply pipe 31 passes through the openings at different heights on the right panel of the model box, and extends into the model box for 3-5 cm. The gap at the opening is filled with sealing material to prevent water leakage. The outlet of the water supply pipe 31 is sealed with a filter membrane to prevent soil samples from entering. inside the tube. The water supply tank 30 and the pressure pump 29 are connected through a water supply pipe 31, and the water supply pipe 31 is provided with a valve 25 for sending water to different heights to realize groundwater level simulation.

The seepage tracing device includes a paint supply tank 32 and a paint tube 33. The paint tube 33 is arranged close to the front panel of the model box, and is erected in the shallow soil layer along the axis direction. The tank 32 is erected above the model box, and the paint tube 33 is provided with a valve to control the replenishment of the paint, and the diffusion of the paint under the action of seepage can track the seepage distribution at the location.

When the simulation test system is implemented, the specific steps are as follows:

(1) Install the model box 1, and use silicone structural adhesive to bond the panels. The shield support 13 is welded and fixed, and the semicircular shield shell 12 is bonded to the shield support 13 and the front panel 11 of the model box, and the left side is aligned with the opening of the left panel of the model box 1 .

(2) Install the shield tunneling system 3. The soil bin partition 14 is installed in the shield model 2, the soil and water pressure sensor 10 is arranged in front of the soil bin partition 14, the transmission rod 16, the axial force gauge 15, the transmission 18 and the servo motor A19 are connected, and the drain pipe 24 is connected to the On the conveyor 22, the rear end of the conveyor 22 is connected to the servo motor B23, and then the front end of the conveyor 22 is installed at the muck outlet 21 at the lower part of the bulkhead 14 of the soil bin, and a section of sealing glue 28 is filled.

(3) Install the water level control device 4, fill the gap at the opening with sealing material, and check whether there is water leakage in the model box 1. If there is water leakage, seal the water leakage.

(4) When calibrating no soil sample, the moving speed of the soil bin partition 14 and the reading of the axial force meter 15 caused by the friction between the panel and the semi-circular shield shell 12 at different speeds.

(5) Move the soil bin partition 14 to 1/3 of the front end of the semi-circular shield shell 12, and fill with the improved muck 34.

(6) The soil sample 7 is filled in the model box 1 by the falling rain method. When the height of the soil sample 7 meets the model height corresponding to the shallow tunnel, the seepage tracer device is installed, and the paint tube 33 is arranged along the front panel 11 of the model box, and the outlet Buried in shallow soil.

(7) A digital photographic camera 8 and a supplementary light source 9 are erected in front of the front panel 11 of the model.

(8) Add water to the model box 1 through the water level control system 4 to simulate the groundwater level.

(9) After the water level is stable, open the valve 25 on the drain pipe 24, start the shield tunneling system 3, push the soil bin partition 14 forward, and the conveyor 22 starts to operate to drain soil. At the same time, the valve 25 on the paint tube 33 of the seepage tracer device 5 is opened.

(10) The seepage law of groundwater is displayed by the seepage tracer device. The soil and water pressure sensor 10 in front of the soil bin partition 14 observes the pressure distribution and fluctuation law of the soil bin. The camera records the picture and the displacement of the soil body on the symmetry plane can be obtained by PIV analysis. Field and velocity field, the change in the reading of the axial force gauge 15 can analyze the stress relief of the excavation face. From this, the stable state of the excavation face is analyzed, and the instability development process and stage characteristics of the large-diameter shield excavation face under the action of seepage are revealed.

Using the large-diameter earth pressure shield tunnel excavation interface simulation test system provided in this embodiment, different test conditions can be set to carry out the following control tests:

Under the condition that the groundwater level and the soil discharge speed of the conveyor 22 remain unchanged, different propelling speeds of the soil bin partitions 14 are set to study the influence of the driving speed on the instability of the driving surface; Under the same condition, different soil dumping speeds of the conveyor 22 are set to study the influence of soil dumping speed on the instability of the driving face.

Different groundwater levels are set, and the seepage effect is more obvious when the groundwater level is higher. The influence of seepage on the stability of the excavation face is analyzed, and the instability mechanism of the excavation face induced by seepage is revealed.

The shield model 2 was not filled or filled with different improved slag 34 prepared in the laboratory test, and the inhibitory effect of different improved slag on seepage was compared and analyzed.

Claims (7)

1. The utility model provides a major diameter earth pressure shield tunnel tunnelling interface analogue test system, includes the mold box, the shield constructs the model, monitoring system, its characterized in that: the device is also provided with a shield tunneling system, a water level control device and a seepage tracing device;

the model box is a rectangular cube, the peripheral panels are made of transparent high-strength organic materials, a semicircular opening for installing a shield model and an opening for installing a shield tunneling system are respectively formed in one side panel of the model box, and a plurality of openings with different heights for installing water supply pipes of a water level control system are formed in the other opposite side panel of the model box; filling a soil sample in the model box;

the shield tunneling system comprises a soil bin control device and a soil discharging and water discharging control device; the soil bin control device comprises a soil bin partition plate, a shaft force meter, a transmission rod, a recording device, a transmission, a driving device and an external support; the soil bin partition plate is a semicircular panel and is arranged between the inner concave surface of the semicircular shield model shell and the front panel of the model box, and a muck outlet is formed in the lower part of the soil bin partition plate; the soil bin partition plate, the axial force meter and the transmission rod are sequentially connected, the transmission rod penetrates through one side panel of the model box and is connected to a speed changer outside the model box, the speed changer is connected with a driving device, and the driving device is fixed on an external support; one end of the recording device is fixed on the external support, and the other end of the recording device is connected to the soil bin partition plate; the soil bin partition plate moves in the semicircular shield shell under the control of the transmission rod; the axial force meter is used for testing the pressure of the movable panel, and the recording device is used for testing the moving distance of the movable panel; the driving device provides power for the movement of the movable panel, and the transmission is used for controlling the forward and backward speeds of the movable panel; the soil discharging and water discharging control device comprises a conveyor, a power device, a water discharging pipeline, a valve, a flowmeter and a waste water tank, wherein the conveyor is arranged at a residue soil outlet at the lower part of the soil bin partition plate, the conveyor penetrates through one side panel of the model box and is connected to the power device, and the power device is fixed on an external support; an opening below the conveyor is connected with a drain pipe, a water outlet valve and a flowmeter are arranged on the drain pipe, and the drain pipe is connected with a wastewater tank;

the water level control system comprises a pressure pump, a water replenishing tank, a water supply pipe and a valve; the water supply tank and the pressure pump are connected through a water supply pipe; a plurality of water supply pipes which are longitudinally arranged penetrate through an opening on one side panel of the model box and are inserted into the filling soil samples at different heights in the model box, and the outlets of the water supply pipes are sealed by filter membranes; a valve is arranged on the water supply pipe, the water level in the model box is controlled, the water supply pipe opening valves at different heights are selected, and the soil sample filled in the model box is filled with water, so that the soil sample at the upper part of the water level is in an unsaturated state, and the underground water level simulation is realized;

the seepage tracing device is arranged at the top of the model box and comprises a pigment pipe and a pigment supply tank, and the pigment pipes are inserted into a shallow soil layer filled with soil samples in the model box from the top of the model box along the axial direction and are arranged at a position close to a front panel in the model box; the pigment pipe is provided with a valve for controlling the supplement of the pigment;

the monitoring system comprises a digital photographic camera and soil and water pressure sensors; the digital photographic camera is arranged outside the front panel of the model box and used for recording the change condition of the soil sample in front of the tunneling surface in the test process; the soil and water pressure sensors are arranged on the soil bin partition plate and used for observing the pressure distribution and fluctuation rule of the driving surface.

2. The large-diameter earth pressure shield tunneling interface simulation test system according to claim 1, characterized in that: the improved muck is filled in the front inner space of the soil bin partition plate of the shield model, and the improvement of the dug soil body in the soil bin of the large-scale soil pressure shield machine is simulated.

3. The large-diameter earth pressure shield tunneling interface simulation test system according to claim 1, characterized in that: the driving device and the power device adopt servo motors.

4. The large-diameter earth pressure shield tunneling interface simulation test system according to claim 1, characterized in that: the recording device adopts a linear displacement sensor.

5. The large-diameter earth pressure shield tunneling interface simulation test system according to claim 1, characterized in that: the conveyer adopts a tubular screw conveyer, and the screw speed is controlled by a power device to realize quantitative soil discharging and water discharging control; and sealing clay is filled in the pipe of the tubular screw conveyor in advance.

6. The large-diameter earth pressure shield tunneling interface simulation test system according to claim 1, characterized in that: and a supplementary light source is arranged outside the front panel of the model box.

7. The large-diameter earth pressure shield tunneling interface simulation test system according to claim 1 or 5, characterized in that: the lower part of the conveyor, which is close to the residue soil outlet, is provided with an opening, the opening is sealed by a filter membrane, and the opening is connected with a drain pipe.

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